Construction Joint Ventures - Schedule of Unconsolidated Construction Joint Ventures Assets and Liabilities (Parenthetical) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Construction Joint Venture
Performance Guarantees	$ 88.2	$ 88.6
Unconsolidated Joint Venture Back charges claims	15.6	11.8
Deficit in unconsolidated construction joint venture	11.5	15.9
Reporting Entitys Interest in Joint Venture [Member]
Construction Joint Venture
Affirmative Claim Recovery Estimate	$ 78.1	$ 74.3